The present invention relates generally to a valve which may be used to regulate the flow of molten metal and the like.
In various industrial operations, it is often desirable to transfer molten metal in bulk from a first container to a second container. Such transfer may be effected by a metal pump immersed in a bath of molten metal in the first container. Operation of the metal pump draws the molten metal through an appropriate conduit to the second container. One application in which such bulk transfer techniques are often utilized is ingot formation.
While metal pumping techniques have proven useful in bulk transfer applications, they have generally been unsuccessful in operations requiring a relatively precise amount of molten metal. One such application is the casting of metal articles, such as bearings. For example, bearings are often cast from the class of metals referred to as white metals, or more specifically "babbitt". Babbitt metal is an antifriction alloy which may include different ratios of lead, antimony and tin depending on the particular article which is to be cast.
The casting of bearings or similar articles from babbitt metal has typically been accomplished utilizing relatively labor intensive techniques. For example, the molten babbitt metal is often removed manually from the bath by a worker using a ladle. The worker then carries the ladle of molten babbitt metal, which may typically weigh 40 pounds or more, to a casting mold.
In the case of a relatively large bearing, three or more such ladles (or even buckets) may be required to complete the casting process. As a result, a worker in this hot environment may quickly become fatigued. Additionally, when more than one ladle is required to cast a bearing, various discontinuities may develop in the structure of the metal.
In an effort to improve the casting process, some gravity feed arrangements have been utilized. For example, in one such arrangement, a bung is inserted into a hole of a bottom of a container in which the molten babbitt metal is maintained. When it is desired that the metal flow into a casting mold, the bung is removed. While this arrangement is somewhat less labor intensive than the ladling technique discussed above, it is difficult to meter relatively precise amounts of the molten white metal into the casting mold.